Karine Hadaya

Successful treatment of recurrent focal segmental glomerulosclerosis after kidney transplantation by plasmapheresis and rituximab

A 22‐year‐old patient whose primary kidney disease was focal segmental glomerulosclerosis (FSGS) developed severe recurrence of proteinuria (up to 57 g/24 h) immediately after a haploidentic living donor kidney transplantation despite pre‐operative plasmapheresis. The immunosuppressive treatment consisted of tacrolimus, mycophenolate mofetil, basiliximab and steroids. He underwent 10 plasmapheresis sessions in the first 3‐week post‐transplantation. In addition, he received 2 i.v. doses of rituximab (RTX) 600 mg (375 mg/m2) on days 7 and 15. Proteinuria decreased below nephrotic range at day 14 and serum creatinine returned progressively to normal values. A short course of oral ciclophosphamide (100 mg/j) was administrated between days 22 and 40 and three additional plasmapheresis sessions on days 34, 39 and 49. This strategy allowed obtaining sustained full remission of the nephrotic syndrome (NS) and excellent graft function, which persists over 2 years after transplantation. No notable adverse events related to RTX or plasmapheresis were observed. This case suggests that RTX associated with plasmapheresis may be an effective treatment of recurrent NS because of FSGS.

De novo anti-HLA antibody after pandemic H1N1 and seasonal influenza immunization in kidney transplant recipients

In solid organ transplanted patients, annual influenza immunization is strongly recommended because of morbidity and mortality of influenza infections. In 2009, the rapid spread of a novel H1N1 influenza A virus led to the accelerated development of novel pandemic influenza vaccines. In Switzerland, the recipients received one dose of seasonal influenza and two doses of AS03‐adjuvanted H1N1 vaccines. This situation provided a unique opportunity to analyze the influence of novel adjuvanted influenza vaccines on the production of de novo anti‐HLA antibodies. We prospectively followed two independent cohorts including 92 and 59 kidney‐transplanted patients, assessing their anti‐HLA antibodies before, 6 weeks and 6 months after vaccination. Sixteen of 92 (17.3%) and 7 of 59 (11.9%) patients developed anti‐HLA antibodies. These antibodies, detected using the single antigen beads technology, were mostly at low levels and included both donor‐specific and non‐donor‐specific antibodies. In 2 of the 20 patients who were followed at 6 months, clinical events possibly related to de novo anti‐HLA antibodies were observed. In conclusion, multiple doses of influenza vaccine may lead to the production of anti‐HLA antibodies in a significant proportion of kidney transplant recipients. The long‐term clinical significance of these results remains to be addressed.

Donor-specific antibody levels and three generations of crossmatches to predict antibody-mediated rejection in kidney transplantation.

Background. This study evaluated the prognostic impact of pretransplant donor-specific anti-human leukocyte antigen antibodies (DSA) detected by single-antigen beads and compared the three generations of crossmatch (XM) tests in kidney transplantation. Methods. Thirty-seven T-cell complement-dependent cytotoxicity crossmatch (CXM) negative living donor kidney recipients with a retrospectively positive antihuman leukocyte antigen antibody screening assay were included. A single-antigen bead test, a flow cytometry XM, and a Luminex XM (LXM) were retrospectively performed, and the results were correlated with the occurrence of antibody-mediated rejections (AMRs) and graft function. Results. We found that (1) pretransplant DSA against class I (DSA-I), but not against class II, are predictive for AMR, resulting in a sensitivity of 75% and a specificity of 90% at a level of 900 mean fluorescence intensity (MFI); (2) with increasing strength of DSA-I, the sensitivity for AMR is decreasing to 50% and the specificity is increasing to 100% at 5200 MFI; (3) the LXM for class I, but not for class II, provides a higher accuracy than the flow cytometry XM and the B-cell CXM. The specificity of all XMs is increased greatly in combination with DSA-I values more than or equal to 900 MFI. Conclusions. In sensitized recipients, the best prediction of AMR and consecutively reduced graft function is delivered by DSA-I alone at high strength or by DSA-I at low strength in combination with the LXM or CXM.

Eculizumab in acute recurrence of thrombotic microangiopathy after renal transplantation

Renal thrombotic microangiopathy (TMA) is a severe complication of systemic lupus erythematosus (SLE), which is associated with the presence of antiphospholipid (aPL) antibodies. In its most fulminant form, TMA leads to a rapid and irreversible end‐stage renal failure. Eculizumab, an anti‐C5 monoclonal antibody, is a novel therapy of choice for patients with paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome. Here, we report the case of a 27‐year‐old woman, known for SLE and end‐stage renal disease due to fulminant TMA. Both aPL antibodies and antinucleosome antibodies were positive. The patient underwent a living‐related kidney transplantation with immediate production of urine. Although serum creatinine was remaining high, a graft biopsy, performed on day 6, demonstrated a TMA recurrence. Despite a treatment with plasma exchange, the situation got worse and dialysis was started. Eculizumab treatment was subsequently administered and renal function improved rapidly. Three months after transplantation, serum creatinine was at 100 μmol/L, without proteinuria. This case illustrates the benefit of eculizumab therapy in a fulminant recurrence of TMA after kidney transplantation, resistant to classical therapy.

Natural killer cell receptor repertoire and their ligands, and the risk of CMV infection after kidney transplantation.

Cytomegalovirus (CMV) infection is the most common viral complication after solid organ transplantation (SOT). Whilst current immunosuppression is known to impair antiviral‐specific T‐cell immunity in SOT, a potential role for natural killer (NK) cells not affected by immunosuppressive therapy remains to be determined. To address this, we compared the genotype of the NK immunoglobulin‐like receptor (KIR) genes and their HLA cognate ligands to the rate of CMV infection in 196 kidney transplant recipients. We have shown that the absence of the HLA‐C ligand for inhibitory KIR and the presence of activating KIR genes in the recipients were both associated with a lower rate of CMV infection after transplantation. In a cohort of 17 recipients with acute CMV infection, NK cells were phenotyped over a period of time after diagnosis by their expression profile of C‐type lectin receptors and capacity to secrete IFN‐γ. The increased expression of the activating C‐type lectin receptors NKG2C and NKG2D was paralleled by the decreased IFN‐γ secretion during the early phase of CMV infection. In conclusion, our findings suggest that KIR/HLA genotype and expression of NKG2C and NKG2D might play a significant role in regulating NK cell function and anti‐CMV immunity after kidney transplantation.

Sequential Kidney/Islet Transplantation: Efficacy and Safety Assessment of a Steroid-Free Immunosuppression Protocol

The aim of this study was to assess the efficiency and safety of the Edmonton immunosuppression protocol in recipients of islet‐after‐kidney (IAK) grafts. Fifteen islet infusions were administered to 8 patients with type 1 diabetes and a functioning kidney graft. Immunosuppression was switched on the day of transplantation to a regimen associating sirolimus‐tacrolimus‐daclizumab. Insulin‐independence was achieved in all patients for at least 3 months, with an actual rate of 71% at 1 year after transplantation (5 of 7 patients). After 24‐month mean follow‐up, five have ongoing insulin independence, 11–34 months after transplantation, with normal HbA1c, fructosamine and mean amplitude of glycemic excursions (MAGE) values. Results of arginine‐stimulation tests improved over time, mostly after the second islet infusion. Severe adverse events included bleeding after percutaneous portal access (n = 2), severe pneumonia attributed to sirolimus toxicity (n = 1), kidney graft loss after immunosuppression discontinuation (n = 1), reversible humoral kidney rejection (n = 1) and fever of unknown origin (n = 1). These data indicate that the Edmonton approach can be successfully applied to the IAK setting. This procedure is associated with significant side effects and only patients with stable function of the kidney graft should be considered. The net harm versus benefit has not yet been established and will require further studies with larger numbers of enrolled subjects.

Expansion and tissue infiltration of an allospecific CD4+CD25+CD45RO+IL-7Rαhigh cell population in solid organ transplant recipients

It has been recently shown (Seddiki, N., B. Santner-Nanan, J. Martinson, J. Zaunders, S. Sasson, A. Landay, M. Solomon, W. Selby, S.I. Alexander, R. Nanan, et al. 2006. J. Exp. Med. 203:1693–1700.) that the expression of interleukin (IL) 7 receptor (R) α discriminates between two distinct CD4 T cell populations, both characterized by the expression of CD25, i.e. CD4 regulatory T (T reg) cells and activated CD4 T cells. T reg cells express low levels of IL-7Rα, whereas activated CD4 T cells are characterized by the expression of IL-7Rαhigh. We have investigated the distribution of these two CD4 T cell populations in 36 subjects after liver and kidney transplantation and in 45 healthy subjects. According to a previous study (Demirkiran, A., A. Kok, J. Kwekkeboom, H.J. Metselaar, H.W. Tilanus, and L.J. van der Laan. 2005. Transplant. Proc. 37:1194–1196.), we observed that the T reg CD25+CD45RO+IL-7Rαlow cell population was reduced in transplant recipients (P < 0.00001). Interestingly, the CD4+CD25+CD45RO+IL-7Rαhigh cell population was significantly increased in stable transplant recipients compared with healthy subjects (P < 0.00001), and the expansion of this cell population was even greater in patients with documented humoral chronic rejection compared with stable transplant recipients (P < 0.0001). The expanded CD4+CD25+CD45RO+IL-7Rαhigh cell population contained allospecific CD4 T cells and secreted effector cytokines such as tumor necrosis factor α and interferon γ, thus potentially contributing to the mechanisms of chronic rejection. More importantly, CD4+IL-7Rα+and CD25+IL-7Rα+ cells were part of the T cell population infiltrating the allograft of patients with a documented diagnosis of chronic humoral rejection. These results indicate that the CD4+CD25+IL-7Rα+ cell population may represent a valuable, sensitive, and specific marker to monitor allospecific CD4 T cell responses both in blood and in tissues after organ transplantation.

Monitoring of cytomegalovirus infection in solid-organ transplant recipients by an ultrasensitive plasma PCR assay.

ABSTRACT Early and accurate monitoring of cytomegalovirus (CMV) infection in solid-organ transplant recipients is of major importance. We have assessed the potential benefit of an ultrasensitive plasma-based PCR assay for renal transplant recipients. The pp65 CMV antigen (pp65 Ag) assay using leukocytes was employed as a routine test for the monitoring of CMV in 23 transplant recipients. We compared the pp65 antigenemia with the CMV load quantified by an ultrasensitive PCR (US-PCR) with a limit of detection of 20 CMV DNA copies/ml of plasma. CMV infection was detected in 215 (67%) of 321 plasma samples by the US-PCR compared with 124 (39%) of 321 samples by the pp65 Ag assay. The US-PCR assay permitted the detection of CMV infection episodes following transplantation a median of 12 days earlier than the pp65 Ag assay. Moreover, during CMV infection episodes, DNA detection by the US-PCR was consistently positive, whereas false negative results were frequently observed with the pp65 Ag assay. We found a good correlation between the two assays, and the peak viral loads were significantly higher in patients with CMV-related complications (median, 5,000 DNA copies/ml) than in those without symptoms (1,160 DNA copies/ml) (P = 0.048). In addition, patients that did not require preemptive therapy based on the results of the pp65 assay had CMV loads significantly lower (median, 36 DNA copies/ml) than those that needed treatment (median, 4,703 DNA copies/ml) (P < 0.001). These observations provided cutoff levels that could be applied in clinical practice. The ultrasensitive plasma-based PCR detected CMV infection episodes earlier and provided more consistent results than the pp65 Ag assay. This test could improve the monitoring of CMV infection or reactivation in renal transplant recipients.

Telomeric rather than centromeric activating KIR genes protect from cytomegalovirus infection after kidney transplantation

Cytomegalovirus (CMV) infection is a common complication after organ transplantation. Previous studies have demonstrated that activating killer‐cell immunoglobulin‐like receptors (KIR) may reduce the rate of CMV infection. KIR genes can be divided into haplotype A (containing a fixed set of inhibitory receptors) and haplotype B (carrying additional activating KIR genes). The KIR locus is divided into a centromeric and a telomeric portion, both of which may carry A or B haplotype motifs. We studied a cohort of 339 kidney transplant recipients to elucidate which KIR genes protect from CMV infection. CMV infection occurred in 139 patients (41%). Possession of telomeric (hazard ratio 0.64, 95% confidence interval 0.44–0.94, p = 0.02) but not centromeric (HR 0.86, 95% CI 0.60–1.23, p = 0.41) B motifs was associated with statistically significant protection from CMV infection. Due to linkage disequilibrium, we were not able to identify a single protective gene within the telomeric B complex (which may contain the KIR2DS1, KIR3DS1, KIR2DL5A and KIR2DS5 genes). The presence of known or putative ligands to activating KIR did not significantly modify the influence of telomeric B group genes. We confirm that B haplotypes protect from CMV infection after kidney transplantation and show that this arises from telomeric B haplotype genes.

Invasive zygomycosis in transplant recipients

Abstract:  Zygomycosis are rare fungal infections occurring mainly in immunocompromised patients. To date only 160 cases have been published in transplant recipients. We report four new cases of zygomycosis in transplant recipients illustrating the large clinical spectrum of this infection: one disseminated infection with heart involvement and one rhinocerebral infection with dissemination in two bone marrow transplant recipients, one cutaneous infection in a liver and one pulmonary infection in a kidney recipient. All cases, except the cutaneous infection that was accessible to surgical resection and a systemic antifungal treatment, were fatal. In transplant recipients cumulating risk factors for zygomycosis, a high index of suspicion is required. Early diagnosis and combining surgery with systemic amphotericin‐B are mandatory to improve survival rates.